A heads up for visitors headed to the park this summer and planning to enter/exit via the Mt Carmel Highway:
https://www.nps.gov/zion/planyourvisit/large-vehicles.htm
https://zionarea.udot.utah.gov/road-restrictions-2/
As of today, this ban will affect travelers driving large RVs, towed trailers/campers, tour buses and other vehicles of larger sizes. As stated in the link from the park's website, measure your vehicle and pull-behinds carefully and pre-plan an alternate route into the park if needed.
Having traveled the very scenic Mt. Carmel Highway and tunnel multiple times, we've experienced the back-up delays caused by the previous one-way escort required for large vehicles to pass through the tunnel. The new restrictions will ease that problem and increase safety on narrow road with hairpin turns and steep drop-offs. The weight of larger vehicles was also causing infrastructure damage to a road that wasn't built to accommodate it.
So enjoy one of the U.S. most-visited parks but plan ahead if camping or even just passing through.
Of interest: This is how one tour company has been managing access to this scenic route and tunnel even before this latest ban.
https://www.southwestadventuretours.com/blog/post/zions-new-tunnel-restrictions-are-here-what-tour-operators-need-to-know/
NOTE: These restrictions are in addition to longtime vehicle bans on the Zion Canyon Scenic Drive: no private cars or tour vehicles are allowed outside of a few winter months. Overnight guests of Zion Lodge (permit) are only allowed as far as the lodge. Travel to trailheads and scenic stops in Zion Canyon is via free park shuttle buses, on foot or two wheels. (Pedestrians and bikes are not allowed through the Mt. Carmel Highway tunnel.)
https://www.nps.gov/zion/planyourvisit/zion-canyon-shuttle-system.htm